1. Field of the Invention
The present invention relates to a multi-channel receiver, and more particularly to a multi-channel receiver capable of minimizing interference effects among receivers.
2. Description of the Related Art
A terrestrial digital multimedia broadcasting (DMB) receiver, a mobile TV receiver, and the like generally use a low intermediate frequency (hereinafter, referred to as low-IF) band. A receiver that uses the low-IF band down-converts a radio frequency (hereinafter, referred to as RF) signal received through an antenna into a low-IF signal of which frequency is relatively lower than that of the RF signal and uses the low-IF signal. In general, the RF signal is down-converted by a down-conversion mixer.
Recently, a function of receiving terrestrial DMB signals and a function of mobile TV signals are included in a navigator or mobile phone. A service for providing various data is provided by mounting a multi-channel receiver including at least two receivers on the navigator or mobile phone.
FIG. 1 is a schematic view illustrating a multi-channel receiver.
Referring to FIG. 1, in a multi-channel receiver 10, two receivers 11 and 12 convert an RF signal received through a common antenna 20 into first and second IF signals IF1 and IF2, respectively.
The common antenna 20 receives signals in a predetermined frequency band. There are a plurality of channel signals that use frequency bands obtained by dividing the entire frequency band. Since channels exclusively use the divided frequency bands, there is no problem in a case where the two receivers 11 and 12 respectively receive signals of different channels. However, when the two receivers 11 and 12 receive signals of the same channel, frequencies of local oscillation frequency signals (not shown) supplied to the first and second receivers 11 and 12 are the same. In this case, a voltage controlled oscillator (not shown) for supplying local oscillation frequency signals to the first and second receivers 11 and 12 and a frequency synthesizer (not shown) generate signals with the same frequency. Although the frequencies of the signals are the same, phases of the signals may be different from each other. Accordingly, an interference effect between the first and second receivers 11 and 12 is amplified, thereby deteriorating performance of the multi-channel receiver.